Topic Essays
From the week ending September 19, 1997
Plant Life of the Rainforest
SFS Interns: Cathy Bierly, Marcella DeAgostino, and Natasha LitchfieldWhen you first glance at a rainforest-covered mountain it looks like a typical forest that you might find in North America. Upon closer inspection the difference is apparent. Once inside the rainforest you are overcome by the diversity of plant life and how lush everything appears. Some of the trees are enormous and have been growing for hundreds of years. The diversity becomes even more obvious once you start learning the names of different species.
Often, the rainforest is visited by tourists. To limit the impact that tourists may have on the plant life, boardwalks are placed through the forest. Many unknown plant species have colored tags on them. When you see the number of tags throughout the forest you realize just how many plants we have left to name or identify.
Some species of plants can only be found in this geographic location. Certain areas of rainforest are thought to be very similar in appearance to what they looked like 20 million years ago. When looking at the plants of the rainforest, one cannot forget how many different animals are dependent on them. At any one time in the year some plant or tree is producing fruit in the Australian rainforest. The plant diversity sustains the animal diversity. If there weren't so many edible plant products such as seeds, fruits, flowers and leaves, there would not be as many animals. If these plants which sustain animal life go extinct, animal extinction will follow closely behind unless animals find an alternate food source.
The trees and plants are also dependent on each other. Some trees block the sunlight for shade tolerant species. Trees, when they fall, decompose and fertilize the soil which keeps the rainforest cycle going. All of these plant cycles are being studied by scientists, along with the potential benefits of rainforest products. Scientists are just beginning to scratch the surface of knowledge contained within the rainforest.
Tropical Reforestation
Festus E. FasehunThe tropical rainforest is the most complex environment on earth. It is the most luxuriant of all plant communities. It is a closed canopy of dense evergreen forest 45m or more tall, characterized by a large number of plant species occurring together. In the rainforest there is a complex diversity and interdependence of plants and animals. For example; the shade tolerant plants germinating under the canopy of trees, lianas and vines reaching the upper layers by utilizing the trees as ladders; stranglers (e.g. Ficus plants) surrounding very large trunks; epiphytes and liverworts growing on leaves and branches; lichens covering the barks of trees; orchids growing in the humus deposited on the axial of branches in the crown; micro-organisms (e.g.. fungi and bacteria) decomposing the wood and leaf litter; ants feeding on floral parts; insects pollinating flowers; birds and rodents feeding on fruits and dispersing seeds; and herbivores grazing on the seedlings on the forest floor.
The tropical rainforest is a dynamic system in which the ecological features of individual members are linked. The tropical rainforests develop where there is abundant rainfall and high temperature and where every month is wet or there are only short dry periods. It is called an evergreen rainforest when it occurs where there is a continuos humid warm climate, where there are distinct rainy or dry seasons they are referred to as rain and monsoon/seasonal rainforest or semi-evergreen. Tropical rainforests occur in all three tropical land masses: South America, Africa and Asia/Pacific including Australia. The largest tropical rainforests occur in South America with about half the global total, 4x106 km2 in an area containing one sixth of the total broad leaf forest of the world. The second is Asia including Pacific and Australia which is estimated to cover 2.5x106 km2. Africa has the smallest block of tropical rainforest 1.8x106km2 in area.
Although the tropical rainforest make up less than 10% of the whole world total land area, they contain more than half of the worlds flora and fauna. Tropical rainforests are important in maintaining species bio-diversity, production of timber, food and medicinal plants, improvement of water catchment area and water quality; stabilization of soil and erosion control; recreation and ecotourism, wildlife habitat, among others things.
Here at the Center for Rainforest Studies we have about 2,000mm (7 ft.) of rain per year. Now that is a lot of water, and it means that things are usually wet, very wet! In most places after a rain, when the sun comes out, things dry fairly fast, this is a result of the sunlight reaching the ground. In the rainforest, because of all the leaves in the canopy, the sun rarely reaches the ground and things never get very dry.
Things have to be done differently here because of the moisture. We have computers but have many problems using floppy disks. Disks are a perfect place for mold to grow and this ruins the disk and disk drives. This has caused many headaches to students and means that all data must be stored on the computer hard drives. The mold also gets into your clothes, shoes, camera, binoculars, furniture, and everything else. It also gets into scientific equipment so it must be very well sealed and cleaned regularly.
The rainforests also present a few animals that make life a little unpleasant. The students are always shocked when they get their first leech. The leeches get on your skin and clothes as you walk through the forest. These leeches are not poisonous but can surprise you. When everything dries out along comes the ticks. These crawl onto you as you walk, sometimes embedding themselves in your skin. Only one species carries a disease, and although they are unsightly, they are generally not dangerous. Both leeches and ticks can be combated by wearing long pants and long sleeved shirts, which may be a bit uncomfortable in the hot and humid rainforest.
One final problem we face is learning the staggering number of plant and animal species that exist in the rainforest. It is said that on the 1 kilometer you drive along our access road you pass more species of plants than are found in all of the USA. This can discourage the students at first, but as they become used to the diversity they soon learn to recognize many of the species. In the end working in the rainforest can be a great experience. Because of the diversity it is constantly full of surprises and provides an opportunity to see and work with some of the most beautiful plants and animals in the world.